This nonprovisional application claims priority under 35 U.S.C. xc2xa7 119(a) on Patent Application No. 2001-186335 filed in Japan on Jun. 20, 2001, the entirety of which is herein incorporated by reference.
The present invention relates to vehicular suspensions, and more particularly to a suspension structure favorable for decreasing structural weight and reducing the costs, e.g., of manufacture, of the suspension structure.
A double wishbone type suspension is a known vehicular suspension structure in the background art. For example, Japanese utility model publication No. Sho 63-48690, describes a xe2x80x9cdouble wishbone type suspension.xe2x80x9d
In FIG. 2 of the above-mentioned publication, the suspension (numerals having a xe2x80x9cxe2x80x2xe2x80x9d, e.g. 13xe2x80x2, are referencing elements from JP 63-48690) includes a suspension arm having an upper arm 13xe2x80x2 and a lower arm 14xe2x80x2 attached to a body frame 1xe2x80x2 (for a reference number, one used in the publication is described as it is). A cross member 15xe2x80x2 for reinforcement is attached to the upper arm 13xe2x80x2, a push-pull rod 12xe2x80x2 is extended from a lower part of the cross member 15xe2x80x2, and an end of the push-pull rod 12xe2x80x2 is coupled to a cushion arm 7xe2x80x2 via a link arm 9xe2x80x2. The cushion arm 7xe2x80x2 is coupled to one end of a cushion unit 10xe2x80x2 via a link arm 8xe2x80x2 and the other end of the cushion unit 10xe2x80x2 is attached to the body frame 1xe2x80x2.
In the above-mentioned suspension, the vertical motion of the upper arm 13xe2x80x2 is converted to the elastic motion of the cushion unit 10xe2x80x2. However, the present inventors have determined that the above-mentioned art suffers from the following problems. A large bending moment acts upon the upper arm 13xe2x80x2 when external force is applied to the cushion unit 10xe2x80x2 via the upper arm 13xe2x80x2 from a front wheel because the push-pull rod 12xe2x80x2 is attached to an intermediate part of the upper arm 13xe2x80x2.
However, the cross member 15xe2x80x2 is required to withstand the bending moment. The cross member 15xe2x80x2 also functions as a coupling member for coupling the upper arm 13xe2x80x2 to the cushion unit 10xe2x80x2. In addition, the push-pull rod 12xe2x80x2, the link arm 9xe2x80x2, the cushion arm 7xe2x80x2 and the link arm 8xe2x80x2 are required to couple the upper arm 13xe2x80x2 and the cushion unit 10xe2x80x2.
As described above, since the reinforcement of the upper arm 13xe2x80x2 is required to couple one end of the cushion unit 10xe2x80x2 to the intermediate part of the upper arm 13xe2x80x2 and multiple parts are required to attach the upper arm 13xe2x80x2, the weight and cost of the suspension and the vehicle is substantially increased.
The present invention overcomes the shortcomings associated with the background art and achieves other advantages not realized by the background art.
An object of the present invention is to provide a reduced weight suspension structure at a reduced cost.
One or more of the objects of the invention is accomplished by a double wishbone suspension structure comprising a wheel side and a vehicle body side; a pair of upper arms and a pair of lower arms vertically swingably to the body side of the suspension structure, the upper and lower arms each having a first end and a second end, wherein the second ends are positioned on the vehicle body side of the suspension structure; an upper coupling shaft and a lower coupling shaft operatively connected to the respective first ends of the upper and lower arms; a knuckle on the wheel side being coupled to the respective first ends of the upper and lower arms via the respective upper and lower coupling shafts; a damper for dampening an impact transmitted from the wheel side to the vehicle body side; and a first end of the damper being coupled to either of the upper coupling shaft or the lower coupling shaft.
One or more of the objects of the invention are also accomplished by a double wishbone suspension structure comprising a wheel side and a vehicle body side; a pair of upper arms and a pair of lower arms vertically swingably to the body side of the suspension structure, the upper and lower arms each having a first end and a second end, wherein the second ends are positioned on the vehicle body side of the suspension structure; a coupling shaft operatively connected to at least one of the first ends; a knuckle on the wheel side being coupled to the at least one first end coupled with the coupling shaft; a damper for dampening an impact transmitted from the wheel side to the vehicle body side; and a first end of the damper being coupled to the coupling shaft.
One or more of the objects of the invention are also accomplished by a a double wishbone suspension structure comprising a wheel side and a vehicle body side; a pair of upper arms and a pair of lower arms vertically swingably to the body side of the suspension structure, the upper and lower arms each having a first end and a second end, wherein the second ends are positioned on the vehicle body side of the suspension structure; a coupling shaft operatively connected to at least one of the first ends; a knuckle having a pair of knuckle coupling parts on the wheel side being coupled to the at least one first end of the arm coupled with the coupling shaft;
a damper for dampening an impact transmitted from the wheel side to the vehicle body side; and a first end of the damper being coupled to the coupling shaft.
Since impact from the wheel is not applied to an intermediate part of the arm, the arm does not require reinforcement and the structure can be reduced in size and weight. The impact from the wheel is not applied to the intermediate part of the arm, because one end of the damper is coupled to a coupling shaft and no bending moment acts upon the arm. A damper attachment for attaching the damper to the arm is also not required. Accordingly, the number of parts can be reduced and the manufacturing cost of the arm can be reduced.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.